Grinding machinery



Jan. 5, 1937. s EINSTEIN 2,066,677

GRINDING MACHINERY Filed Oct. 26, 1931 6 Shets-Sheet 1 y lhmentorGttorncg Jan. 5, 1937. s. EINSTEIN 2,066,677

GRINDING MACHINERY Filed 0012. 26, 1931 6 Sheets-Sheet 2 1&q4

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I GRINDING MACHINERY 'Filed Oct 26, 1951 e Sheets-Sheet s Jan. 5, 1937.s. EINSTEIN 2,066,677

GRINDING MACHINERY Filed oct'. 26, 1951 s Sheets-Sheet 4 Z f: max? I W 4A:

g [if Zmventor s. EINSTEIN 2,066,677

G MACHINERY GRINDIN Filed Oct. 26, 1931 6 Sheets-Sheet 5 Q) s I i I kBuvcntor Gttomcg Jan. 5, 1937. s, ElNSTElN 2,066,677

GRINDING MACHINERY Filed Oct. 26, 1951 6 Sheets$heet 6 llllu J74 V mCttorncg Patented Jan. 5, 1937 UNITED STATES PATENT OFFICE 2,066,677GRINDING MACHINERY setts Application October 26, 1931, Serial No.571,029

36 Claims.

This invention relates to improvements in machine tools and especiallyto improvements in grinding machinery.

An object of thisinvention is the provision of an improved grindingmachine for grinding or generating the hole or bore in hollow workpieces.

Another object of the invention is the provision of an improved internalgrinding machine operating on centerless principles for simultaneouslygrinding or finishing a plurality of work pieces.

A further object of the invention is the provision of a grinding machinefor simultaneous rough and finish grinding of work pieces on a singlemachine, embodying an improved work supporting and rotating mechanismwhereby the work may be advanced from one support to another and rotatedabout the same axis, a result which was extremely difficult withmultiple internal grinding machines of previous constructions.

A still further object of the invention is a provision of a multiplespindle, internal grinding machine operated in accordance with wellestablished centerless grinding principles that is automatic in naturefor continuously finishing work pieces and thereby reducing idle time ofthe machine to the absolute minimum.

Other objects and advantages of the present invention should be readilyapparent by reference to the accompanying drawings illustrating onepossible embodiment of the invention and described in the followingspecification and it is to be understood that any modifications may bemade in the exact structural details there shown and described withoutexceeding the spirit of the invention as defined in the appended claims.

In the drawings:

Figure 1 is a front elevation of a grinding machine embodying theimprovements of this invention.

Figure 2 is a top plan view of the machine illustrated in Figure 1.

Figure 3 is a sectional view taken on line 3--3 of Figure 1.

Figure 4 is an elevational view of certain parts shown in Figure 1 andas seen particularly from line 4-4 thereon.

Figure 5 is a fragmentary sectional view taken on line 55 of Figure 2,certain parts being shown in elevation.

Figure 6 is a fragmentary sectional view through the grinding wheelslide as seen from line 6--6 of Figure 1.

Figure 7 is an elevationalview of the control parts for the slide asseen from ure 1.

Figure 8 is a vertical sectional view through a hydraulic valve forminga detail of the slide control mechanism.

Figure 9 is a sectional view taken on line 99 of Figure 2.

Figure 10 is a sectional view taken on line Ill-l0 of Figure 9.

Figure 11 is a sectional view taken on line ||--ll of Figure 10.

Figure 12 is a sectional view taken on line l2--l 2 of Figure 3illustrating the indexing mechanism for automatically advancing workpieces relative to the grinding throat.

Figure 13 is a top plan view of a modified machine embodying theprinciples of the invention.

Fi ure 14 is an elevational view of the machine shown in Figure 13 beingpartly in section as seen from line I l-l4 of Figure 13.

Throughout the several views of the drawings similar referencecharacters are employed to denote the same or similar parts.

In the past internal grinding machines have been provided for grindingor finishing the internal surface of the bore of cylindrical workpieces. These machines were of the chuck type in which the work wasclamped or secured and rotated with the chuck about the axis of theshaft or spindle to which the chuck was secured. The work piece couldnot be removed from the chuck and later reinserted therein and rotatedabout the identical axis each time nor could the work be transferredfrom one machine to another and rotated about the identical axis. Theinability to mount a work piece in a chuck with the bore of theworkpiece exactly concentric to the axis of. rotation of the chuck hasmade impossible, in precision grinding, the rough grinding of aworkpiece by a wheel of the proper grade and the subsequentrepositioning of the workpiece in the same or another machine for afinish grinding operation by a second wheel of a suitable grade toprovide the desired finish on the workpiece. Accurate grinding to apredetermined diameter has necessitated in the past the completegrinding of the work at the initial chucking and was done by a grindingwheel that was a compromise between the proper roughing wheel and theproper finishing wheel.

By the invention here disclosed the work is rotated on its previouslyfinished external surface so that the said work may be shifted frommachine to machine or from position to position in the same machine and.still rotate about a single line 'l--'I of Figidentical axis. By thismethod the work may be first rough ground at one station of a singlema-' chine, for example, and then advanced to another station for asemi-finishing or a finishing operation thereon. In this way theobjections above noted have been eliminated and work pieces having asatisfactory finish produced.

A device for accomplishing this result may comprise a bed 20, havingformed on its upper surface ways 2| for the work supporting and controlling unit 22 and additional ways 23 for supporting and guiding thegrinding wheel head 24. As will be noted in Figure 1 the ways 2| and 23are at right angles to one another, whereby the work may be positionedso that the operator can readily observe the action of the grindingwheels on the work.

The work holding unit 22 consists of a lower slide 25 mounted upon theways 2| and supporting an upper slide 26 superimposed thereon. The slide26 in turn supports a head 21 in which is journaled a spindle 28, (seeFigure 3). The spindle 28 has secured to its free end a regulating wheel29 composed of suitable abrasive material for frictionally engaging andcontrolling the rotation of the work. The lower slide 25 has secured toit at its inner end a block 38, Fig. 5, from which rises a bracket 3|supporting at spaced intervals thereon work rest blades 32 and 33. Thework rest blades 32 and 33 are each provided with an inclined uppersurface 34 inclining in the direction of the active face of theregulating wheel 29 and forming therewith work receiving troughs. Asseen in Figure 5, the work 35, herein illustrated as a hollowcylindrical bushing, simultaneously engages the surface 34 of the bladesand the. adjacent surface of the regulating wheel 29. The said workpieces are held or retained in their respective positions by means ofpressure rolls 36 and 31, respectively rotatably supported by arms 38and 39, each pivoted as at 48 and 4| to a bracket 42 which is in turnpivoted at 43 to arm 44 carried by the block 30. Springs 45 and 46 areprovided for respectively actuating the arms 38 and 39 toward the workpieces.

The wheel head 24 consists of a main or lower slide 47, Fig. 5, engagingwith the way 23, and is provided on its upper surface with a way 48 forthe supplemental or upper slide 49. This slide 49 has rising from it avertical column 50 provided on its forward face with a dovetailed guide5| on which are mounted a pair of heads 52 and 53, Fig. 1, each headhaving journaled therein a spindle for supporting the grinding wheels 54and 55 respectively.

The grinding wheels 54 and 55 are adapted to simultaneously enter thebores in the work pieces supported by the blades 32 and 33 respectively.The heads 52 and 53 are adjustable independently relative to the column56 by means of screws 56 and 51 respectively, Fig. 5, received inthreaded bosses 58 and 59 extending respectively from the heads 52 and53. Each adjusting screw has secured thereto a bevel gear 60, meshingwith a complementary gear 6| on the end of a shaft 62, said gears beingoperated by hand wheels 63, Fig. 1. The grinding wheels 54 and 55 areadapted to be rotated at a high grinding rate of speed by means of abelt or like 64 extending about pulleys 65 on the ends of the grindingwheel spindles, the belt deriving its power from a pulley 66 secured toand driven by motor 61 mounted on the upper side of slide 49.

The work is adapted to be automatically fed radially into the grindingwheel through the following mechanism. The upper slide 26 has securedthereto a nut 68, Figs. 1 and 9, receiving the threaded end of anadjusting cross feed screw 69 which passes through the housing 10secured to the bed as at H. The screw 69 has secured thereto exteriorlyof the housing 10 a pilot or hand wheel I2 whereby the screw may berotated for adjusting the slide. Interiorly of the housing 18 the screwhas secured to it the slide block 73, Fig. 9, guided in the bearing 14integral with said housing. Pitmans 15 are pivoted at one end as at 16,to the slide block 13 and at their other ends by pins 16a to lugs 11extending from the arm 78. The arm 18 is in turn pivoted at 19 tohousing 10 and carries at its lowermost end a roller received in camgroove 8| of the cam 8|a carried by the cam shaft 82. The cam shaft 82has secured to it a worm wheel 83, Fig. 10, meshing with a worm 84 onworm shaft 85 driven through suitable transmission means 86, Fig. 1, I

from the motor or prime mover 8'! secured to the housing 18 at itslowermost surface.

From the foregoing it will be noted that rotation of the cam 8|-a willoscillate the arm 18 for effecting an axial shifting of the cross feedscrew 69 and slide 26 for effecting a feed of the work toward thegrinding wheel to effect a stock removal therefrom. The rotation of cam8|a also provides for a withdrawal of the workpieces from engagementwith the work rests 32 and 33 and pressure rolls 36 and 31 to makepossible the movement of the workpieces from one grinding position tothe next. The movement of the regulating wheel 29 to withdraw theworkpieces from the work rests and pressure rolls renders the yieldingholding means, that is, the pressure rolls, inoperative while theworkpieces are moved from one grinding position to the next.

As will be noted from the drawings two workpieces will be operated uponsimultaneously, one having a roughing cut performed while the other ishaving the internal bore thereof finish ground. The work pieces areadvanced from the roughing to the finishing station automatically and anunground workpiece automatically brought to the rough grinding position.The mechanism for accomplishing this result comprises a magazine 88,Fig. 5, in which are loaded the workpieces or to which they may be fedby a hopper and are retained therein by means of a spring pressedtrigger 89 pivoted as at 98 to the regulating wheel head 21. An arm 9|pivoted at 92 cooperates with the trigger 89 and holds the work piecesin the magazine during the discharge of the lowermost work piece fromthe magazine. plished through a pin 93 carried by-the arm 9| engagingwith the tail 93a of the trigger 89. For this purpose the arm 9| has anarcuate seat 9|a for engagement with the second lowermost work piece.The operation of these parts is as follows: The trigger 89 is actuatedin a clockwise direction to withdraw the lug 89a .of the trigger 89 fromthe lowermost work piece and allow same to drop from the magazine. Thismovement of the trigger 89 carries with it the tail 93a which pushes onthe pin 93 extending from arm 9| and actuates it in a counter-clockwisedirection to shift the arcuate seat 9|a into holding engagement with thesecond lowermost work piece.

The trigger 89 terminates in a long curved finger 94 adapted to beengaged by the carrying arms 95 of work carrying frame or drum indicatedgenerally in Figure 5 by the numeral 96. As seen in Figure 3 the frameor drum 96 comprises'end plates 91 and 98 joined together by suitablecon- This is accom: i

.rack bar I20.

2,066,677 necting pins 99. The plate 98 is provided with.

an enlarged bore I00 surrounding and spaced from the regulating wheelspindle 28 and lying to the rear of the back face of the said regulatingwheel 29 when seen from the front of the machine. The plate 91 is on theforward side of the regulating wheel 29 and has extending from it asleeve IIII which passes through the cover I02 of the head 21. Thesleeve IOI has secured to its forward end a ratchet I03 being heldagainst relative movement as by the key I04. The sleeve IOI in additionis journaled in a bearing I05 of an adjustable supporting plate bracketI06 to whichis secured a cover I01 enclosing the ratchet I03. Thebracket or plate I06 is held in adjusted position by means of bolts I06which extend through elongated perforations I09 in the forward end ofthe head 21. The plate sleeve IOI has loosely journaled therein a shaftIIO to the end of which is secured the arm III, Figs. 3 and 12, bearingspring pressed pawl II2 for engagement with the teeth of ratchet I03.One end of a link H4 is pivoted at one end to'the arm III and has itsother end adjustably pivoted at II5 to a plate II6 secured to the end ofa stub shaft III. The stub II! is rotatably journaled in the bracket I06near its lowermost end. The plate I I6 is provided on itscircumferential surface with gear teeth II8 meshing with rack teeth II9of This bar I20 extends longitudinally on the front face of the machineand is guided at its rear end in a bearing I2I, Fig. 11, integral withthe housing 10. The terminus of the bar I20 is within the housing I0 andcarrier a roller I22 received in a cam slot I23 formed in the face ofthe cam I24 which is secured byany desirable means to the cam shaft 02.

From the foregoing it will be noted that the work carying frame or drum96 is actuated in timed relation to the in and out movement of theslides 25 and 26. This is accomplished by mounting the cams BI and I24on the same shaft so that they are rotated in unison and kept in timedrelation. The cam I24 in rotating with the 'shifted, rotating the workcarrying drum in a counter clockwise direction. This causes the fingers95 to successively engage with the finger 94 of the trigger 89 forrelieving the pressure against the lowermost work piece in the magazineand permitting it to drop into position for conveyance to the roughingstation for the first operation thereon. At this time the workpiecepreviously roughed is carried down to the finishing station from whichthe previous workpiece has been discharged. It should be noted that thisloading and ejecting of the workpiece takes place when the slides 25 and26 are in their fully retracted position.

In order that the slides may be manually adjusted for setting uppurposes and thelike, the rack bar' I20 is so mounted or constructed asto have the rack teeth Il9 thereof disengaged from the rack teeth H8 ofthe disc I I6 during this adjustment. A readily releasable support isprovided which may comprise, as seen in Figure 4, an arm I25 pivoted atI26 to the adjustable plate or bracket I06. The arm I25 is so mountedthat the weight of the rack bar I20 tends to oscillate it about itspivot in a clockwise position as seen in Figure 4, but this tendency isrestrained by means of the pin I2 'I extending from a latch I28 pivotedat I29 to the plate I06. A spring I30 having opposite ends secured tothe latch I26 and the plate I06, effectively holds the latch and arm I25in position tomaintain proper driving engagement between the rack barteeth II9 and the disc teeth II8. In order to break this drivingconnection it is merely necessary to exert a force on the finger pieceI3I of the latch I28 to overcome the resistance of spring I30, whereuponthe bar I20 drops by gravity breaking the connection with the plate H6.

The grinding wheels are axially reciprocated during the grindingoperation in order to break up grinding lines on the work and providethe most desirable finish thereon. This reciprocation of the wheels isaccomplished by the reciprocation of slides 41 and 49 together with theparts carried thereby by hydraulic pressure acting on opposite sides ofa pistonI32 contained within the cylinder I33. The piston I32 hasextending from it the piston rod I34 connected to the lower end of thearm or bracket I35 secured to the under surface of the lower slide 41.The said bracket I35 extends through a suitable opening in the uppersurface of the bed 20 to the interior thereof where there is mounted theblock or bracket I36 containing the cylinder I33. The block or bracketI36 further has pressed into it, beneath the cylinder I33, a bushing I31forming a sleeve for the spool valve I38 acting as a reversing valve forcontrolling the direction of flow of the hydraulic pressure. As seen inFigure 6 the hydraulic pressure is conveyed to the valve by means ofconduit I39 and is directed to'the port I40 connected with channel I4Iterminating at the right hand end of the cylinder I33 as seen in Figure6. This causes the pressure to actuate the piston I32 to the left asseen in said figure discharging the hydraulic medium ahead of the pistonthrough the channel I42 to the port I43 where it enters the valvebushing I31 and is directed by the valve I36 to the exhaust conduit I44.In response to this movement of the piston I33 the slides 41 and 49 areactuated to the left therewith until the valve I38 is reversed orshifted to its extreme right hand position which is opposite tothatillustrated in Figure. 6. This is accomplished through a reversing leverI45 secured to a shaft ,I46, journaled in the walls of bed 20 andcarrying on its inner end a valve shifter arm I 47, the end of which ispositioned between collars I40 at the end of the piston rod I49 for thevalve I 36.

The lever I45 has extending from it intermediate its end a pin I50adapted to be normally engaged by adjustable dogs I5I and I52 whichnormally determine the limits of the reciprocatory stroke of thegrinding wheels through the work. After the valve 38 has been shiftedfor reversing the flow of .fluid the said flow will be from the conduitI39, port I43, and channel I42, to the left hand'end of the cylinderI33, for actuating the piston I32 therein to the right as seen in Figure6 and exhausting the hydraulic medium therein through the channel I4I,port I40, valve chamber I3I and branch exhaust conduit I53.

The normal reciprocation of the grinding wheels which takes place duringthe actual grinding operation does not completely withdraw the saidwheels from bore of the work so that additional movement must be giventhe wheels at the time the workpieces are shifted from one station tothe next. For this reason the reversing dog I52 is pivotally mounted atI54 on the slidable core I55 of a solenoid I56 which is adjustablycarried by the lower slide 41. The solenoid I56 is included in anormally interrupted electrical circuit whereby the dog I52 lies in aposition to engage the reversing pin I and the said dog I52 is heldagainst movement about its pivot in one direction by a stop I51extending from the core I55. The circuit of the solenoid I56 iscompleted at the time that the cross feed mechanism is procuringretraction of the cross feed movement, said solenoid being energized bythe closing of a switch I58, Fig. 10, in the circuit through the cam I59depressing the movable switch member I60. The energization of thesolenoid I56 retracts the dog I52 from alinement with the pin I50 sothat the slides 41 and 49 continue on past their normal reversing pointretracting the grinding wheels completely from bore of the work, andshifting of the work from one station to the other thus takes placewithout interfering with said grinding wheels. The mechanism is so timedthat the slides continue in a retracting direction and carry with them acam I6I, Fig. 7, which engages through its inclined face I62 adepressible valve actuator I63 for closing a needle valve I64, Fig. 8,in the feed line through which the hydraulic medium flows. This needlevalve is normally open a definite amount to determine the rate of thehydraulic medium and the normal rate of reciprocation of the slides. Theclosing or partial closing of this valve I64 reduces the flow of thehydraulic pressure or medium and thereby slows up the rate of movementof the slides. The slow movement continues until the reversing lever pinI50 is engaged by the dog I65 which is also carried by the slide 41whereupon the reversing of valve takes place. The return movement ofslide 41 is at first a slow one until the cam face I62 rides off thevalve actuator I63 whereupon the previously compressed spring I66expands and returns the valve I64 to its normal proper operatingposition. At this time the work pieces have been properly positioned sothat the grinding wheels now enter the bores therein and the grindingoperation is resumed.

During the operation of the machine, the member 42 is held againstmovement and the feeding action between the grinding wheel and the workpiece is procured by an advancing movement of the regulating wheel 29toward the left, Fig. 1, which urges the work pieces against thegrinding wheels. With the machine in the position of Fig. 5, thegrinding operation on the work pieces continues with the grinding wheels54 and cutting deeper and deeper into the work piece as a result of theforward movement of the wheel 29 until the latter is advanced to apredetermined point as determined by' the cam 8| on the rotating shaft82. As the regulating wheel reaches its forward position, the cam I59which rotates with the cam 8| operates the switch I58, therebywithdrawing the grinding wheels 54 and 55 toward the rear of the machinefor positioning said wheels in spaced axial relation to the bores of thework pieces. During the axial separation of the grinding wheels, theregulating wheel 29 is withdrawn to the right by the cam BI to separatesaid wheel from the work supports 32 and 33 and from the pressure wheels36 and 31, this retracting movement being suflicient to permit the upperwork piece 35 to move-downwardly between the support 32 and theregulating wheel. As the grinding wheel reaches its retracted position,the cam I24 on the shaft 82 procures, through the pawl H2 and theratchet wheel I03, a counterclockwise movement of the carrier 96,thereby shifting the upper work piece 35 downwardly into a position forengagement with the grinding wheel 55 during a subsequent advance of theregulating wheel and releasing the lowermost work piece from themagazine 88 and positioning said work piece for engagement with theupper grinding wheel 54. After the counterclockwise advance of thecarrier 96, the regulating wheel 29 is again advanced by the cam 8Ibringing the spaced work pieces into engagement with the supports 33 and34 and the pressure wheels 36 and 31 for centerless rotation of the workpieces during the subsequent grinding operation. During the advance ofthe work pieces from one grinding station to the next, the carriage 49carrying the grinding wheels moves slowly toward the rear of themachine, the direction of movement being reversed by the dog I so thatwhen the work pieces are in the position of Fig. 5, during the advanceof the regulating wheel 29, the grinding wheels 54 and 55 are returnedaxially toward the work pieces for entry within the bores thereof. Thegrinding operation is then repeated as above outlined.

The modification shown in Figures 13 and 14 embodies the same principlesas above'described and includes a bed I61 of a substantial T-shape. Thearm of the bed has formed on its upper surface, and extending fromopposite ends toward the center thereof, guides I68 and I69 on which arerespectively mounted wheel heads I10 and HI. As above, the wheel headsconsist of a pair of slides I12 and I13, the former being guided by theguide ways I68 and I69, the latter being guided on additional ways I14formed on the slide I12. The upper slide I13 is provided with a threadedportion I14 receiving'the screw I16 rotatably journaled in block I11extending upward from the slide I12. Secured to the screw of I16 wherebyit may be operated is a hand wheel. I18. The upper slide I15 supports amotor I19 geared or belted as by means of belt I to a pulley I8I on theend of a grinding wheel spindle I82 journaled in bearing box I83. Themotor I19 is rotated at a high rate of speed for properly rotating thespindle I82 and small internal grinding wheel I84 secured thereto.

The stem or bed extension I85 is provided with a guide way I86 forguiding the work driving and controlling head I81. The head I 81 hasjournaled in the bearing I88 a spindle to which is secured a pair ofregulating wheels I89 and I90. The wheel head I81 is secured to orformed integral with a slide I9I superimposed on a lower or second slideI92 that engages with the guide I86. Clamps I93 and I94 may be providedfor connecting the slides to one another for movement as a unit relativeto the bed and for securing the lower slide to the bed for independentactuation of the slides. The lower slide I92 carries at its foremost enda, work rest I95 having a pair of supporting surfaces I96 and I91 spacedfrom one another by a center upstanding lug I98 which limits themovement of the work pieces I99 and 200 toward one another.

The slides are independently and jointly adjusted by means of a screw20I threaded into a nut 202 carried by the rear portion of the upperslide I9I in a manner similar to the mounting of nut 60 as shown inFigure 9. The screw is journaled in a box 203 carried by the bed exten-75 sion I85 in a manner similar to the mounting of the adjusting screw69 in box or housing 19. The same mechanism is inclosed within the boxor housing 203 as above described in connection with the box' or housingI9 so that the screw 20 I is axially shifted to effect a relative feedbetween the grinding wheels I84 and the work toeifect the proper stockremoval therefrom.

The slides I12 and I13 are reciprocatedrelative tothe bed I61 and theways I68 and IE9 by the hydraulic means illustrated in connection withFigures 1 to 12 inclusive, the corresponding parts being indicated withprime characters in Figures 13 and 14.

The operation of the modified disclosure is as follows: A Work piece isplaced on the work supporting surface I96 and the machine started inoperation which consists in'axially shifting the head "I from theposition shown in Figure 13 to insert the wheel within the bore in thework piece I99. The work head I81 is then actuated toward the front ofthe machine to feed the work piece and grinding wheel into one another,the grinding wheel reciprocating continuously while in contact with thework. As soon as the work head has been shifted the full amount asdetermined by the cam within the housing 293, it is retracted toseparate the wheel and the .work. Simultaneously the stroke of'thegrinding wheel is extended through the retraction of the normal strokelimiting dog whereupon the grinding wheel of the wheel head II passescompletely out of the work.

The work piece I99 is now placed in the position of the work piece 200and a new unfinished work piece placed onthe supporting surface I96whereupon both wheel heads I10 and III are actuated towards one another.Atthis time the wheel head III is roughing, in the same manner as abovedescribed, the new work piece 'on the supporting face I96 while thegrinding wheel of the head H9 is finishing the previously roughed workpiece.

prising a bed, a plurality of work supports onv the bed for peripheralengagement with work pieces, a rotary drive wheel frictionally'engagingv the peripheries of the work pieces for effecting theirrotation, a plurality of pressure members adjacent said work supportsfor holding the work pieces against the drive wheel, and a grindingwheel for each work support carried by the bed and reciprocable relativeto the work pieces.

2. An internal grinding machine for grinding the bore of hollowcylindrical work pieces commeans for efiecting a relative feedingmovement.

between the grinding wheels and the work pieces on the work supports toreduce the work pieces correspondingly. I

work pieces in the work receiving troughs and 3. In a grinding machine,the combination of a. plurality of work supports, an opposed regulatingwheel forming, with the work supports, work receiving troughs at pointsperipherally spaced along the regulating wheel surface, a plurality ofgrinding wheels corresponding in spacing to the work supports forgrinding the internal bore of work pieces on the work supportssimultaneously, and means for holding the against the regulating wheels.

4. In an internal grinding machine the combination of a bed, grindingwheels carried thereby, a slide carried thereby and translatablerelative thereto, a bracket on the slide, a plurality of work rests onthe bracket, a regulating wheel opposed to the work rests and formingwork receiving troughs thereby, means mounting the regulating wheel onthe slide, pressure means for urging work pieces on each of said workrests into engagement with the regulating wheel, and means'for actuatingthe slide and parts sup-- ported thereby toward the grinding wheels foreffecting a stock removal from the work.

5. In an automatic internal grinding machine the combination of a bed, arotatable friction drive wheel carried by the bed for movement relativethereto, a hopper, a work carrier, a plurality of work supportsperipherally spaced about the friction drive wheel and defining spacedgrinding stations, and means carried by the hopper and carriercooperating with one another to re lease workpieces from the hopper andadvance same to the several grinding stations.

6. In an automatic internal grinding machine the combination of a bed, arotatable friction drive wheel carried-by the bed for movement relativethereto, a hopp'ena work carrier, a plurality of work supportsperipherally spaced about the friction drive wheel and defining spacedand carrier cooperating with one another to release workpieces from thehopper and advance same to the-several grinding stations, means forintermittently actuating the workcarrier, and

means for holding the workpieces in frictional engagement with thefriction drive wheel.

, 7. In an automatic internal grinding machine 'thecombination of a bed,a rotatable friction drive wheel carried by the bed for movementrelative thereto, a hopper, a work carrier, a plurality of work supportsperipherally spaced about the friction drive wheel and defining spacedgrinding stations, means carried by the hopper and carrier cooperatingwith one another to reiease workpieces from the hopper and advance sameto the several grinding stations, means for intermittently actuating thework carrier, means for holding the workpiece in frictional engagementwith the friction drive wheel, a grinding wheel foreach grindingstation, means for reciprocating the grinding wheels within .the boreslide, a second slide superimposed on the main 70 slide, a column risingfrom the second slide, a plurality of wheel heads on the column, meansfor adjusting the wheel heads relative to the column, means foradjusting the slides relative to one another, and means coupled with themain 5- grinding stations, means carriedby. the hopper slide foreffecting the reciprocation thereof and parts carried thereby.

9. A wheel head for internal grinding machines comprising a slide, a bedsupporting the slide, a second slide superimposed on the main slide, acolumn rising from the second slide, a plurality of wheel heads on thecolumn, means for adjusting the wheel heads relative to the column,means for adjusting the slides relative to one another, means coupledwith the main slide for effecting reciprocation thereof and partscarried thereby, said means comprising a piston, a piston rod connectedto the slide, an hydraulic pressure source for axially actuating thepiston, a valve operable to control the direction of flow of thehydraulic medium and consequently the direction of reciprocation of theslide, and dog means for determining the length of stroke of the piston.

10. A wheel head for internal grinding machines comprising a slide, abed supporting the slide, a second slide superimposed on the main slide,a column rising from the second slide, a plurality of wheel heads on thecolumn, means for adjusting the wheel heads relative to the column,means for adjusting the slides for effecting reciprocation thereof andparts carried thereby, said means comprising a piston, a piston rodconnected to the slide, an hydraulic pressure source for axiallyactuating the piston, a valve operable to control the direction of flowof the hydraulic medium and consequently the direction of reciprocationof the slide, dog means for determining the length of stroke of thepiston, and means for rendering the dog means inoperative to eifect anextended stroke of the slide and parts carried thereby.

11. An internal grinding machine for roughing and finishing work piecescomprising a regulating wheel, a slide supporting said wheel, a bracketon the slide having a plurality of work rest blades secured thereto andcooperating with the regulating wheel for forming work receiving troughsdefining spaced grinding stations, a second slide on the bed andshiftable transversely thereof, a grinding wheel for each work supportcarried by the second slide, means for actuating the first slide toeffect a relative feed between the regulating and grinding wheels, andmeans for advancing work pieces from station to station at theconclusion of each grinding operation.

12. An internal grinding machine for roughing and finishing work piecescomprising a regulating wheel, a slide supporting said wheel, a bracketon the slide having a plurality of work rest blades secured thereto andcooperating with the regulating wheel for forming work receiving troughsdefining spaced grinding stations, a second slide on the bed andshiftable transversely thereof, a grinding wheel for each work supportcarried by the second slide, means for actuating the first slide toefiect a relative feed between the regulating and grinding wheels, meansfor advancing work pieces from station to station at the conclusion ofeach grinding operation, said means for feeding the work and wheeltoward one another and for advancing the work from station to stationcomprising a cam shaft, and a pair of cams on the cam shaft each havingoperative connections respectively with the work advancing means and thefeeding means.

13. An internal grinding machine for grinding the bore of hollowcylindrical work pieces comprising a bed, a plurality of spaced worksupports on the bed for peripheral engagement with work pieces, a rotarydrive wheel frictionally engaging the peripheries of the work pieces foreffecting their rotation, a plurality of spaced grinding wheels carriedby the bed and reciprocable relative to the work pieces, means towithdraw said grinding wheels from operative relation to the work, andmeans for procuring advancement of the work pieces from one work supportto the next while said grinding wheels are in inoperative position.

14. An internal grinding machine for grinding the bore of hollowcylindrical work pieces comprising a bed, a plurality of spaced worksupports on the bed for peripheral engagement with work pieces, a rotarydrive wheel frictionally engaging the peripheries of the Work pieces foreffecting their rotation, a plurality of spaced grinding wheels carriedby the bed and reciprocable relative to the work pieces, means foreffecting a radial feeding movement between the grinding wheels and thework pieces to reduce said work pieces, means to procure withdrawal ofsaid grinding wheels relative to the work pieces to inoperativeposition, and means to advance the work pieces to the successive worksupports while said grinding wheels are in inoperative position.

15. An internal grinding machine for grinding the bore of hollow workpieces comprising a bed, a plurality of spaced work supports on the bedfor peripheral engagement with work pieces, a rotary drive wheelfrictionally engaging the peripheries of the work pieces on said worksupports for effecting a rotation of said work pieces, a plurality ofspaced grinding wheels carried by the bed, means for withdrawing saidgrinding wheels from operative relation to the work pieces, and meansfor advancing the work pieces from one work support to the next whilesaid grinding wheels are in inoperative position.

16. An internal grinding machine for grinding the bore of hollow workpieces comprising a bed, a plurality of spaced work supports on the bedfor peripheral engagement with work pieces, a rotary drive wheelfrictionally engaging the peripheries of the work pieces on the worksupports for effecting a rotation of said work pieces, a plurality ofspaced grinding wheels carried by the bed, means for effecting a radialfeeding movement between the grinding wheels and the work pieces forgrinding the latter, means to procure withdrawal of said grinding wheelsrelative to the work pieces to inoperative position, and means toadvance the work pieces to the successive work supports while saidgrinding wheels are in inoperative position.

1'7. An internal grinding machine for grinding the bore of hollowcylindrical work pieces comprising a bed, a plurality of spaced worksupports on the bed for peripheral engagement with work-pieces, a rotarydrive wheel frictionally engaging the peripheries of the work pieces foreffecting their rotation, a plurality of spaced grinding wheels carriedby the bed and reciprocable relative to the work pieces, means towithdraw said grinding wheels from operative relation to the work, andmeans for procuring advancement of the work pieces from one Work supportto the next while said grinding wheels are in inoperative position, andfor simultaneously placing an unground work piece on the first worksupport.

18. In a grinding machine, the combination of a plurality of worksupporting members, an opposed regulating wheel forming, with the worksupporting members, work receiving troughs at ing wheel, and a workcarrier for advancing the work pieces from one support to the next.

19. An internal grinding machine comprising a bed, a plurality of spacedwork supports on the bed for peripheral engagement with work pieces,arotary drive wheel frictionally engaging the peripheries of the workpieces on the work supports for effecting the rotation of said workpieces, a plurality of spaced grinding wheels carried by the bed, meansfor effecting a radial feeding movement between the grinding wheels andthe work pieces for grinding said work pieces, means operating in timedrelation to the feeding means for procuring separation between saidgrinding wheels and the work pieces, and means for advancing the workpieces to the successive work supports while said grinding wheels are ininoperative position.

20. An internal grinding machine comprising a bed, a plurality of spacedwork supports on the bed for peripheral engagement with work pieces, arotary drive wheel frictionally engaging the peripheries of the workpieces on the work supports for effecting the rotation of said workpieces, a plurality of spaced grinding wheels carried by the bed, meansfor eflecting a radial feeding movement between the grinding wheels andthe work pieces for grinding said work pieces,

and a work carrier actuated in timed relation to the feeding means foradvancing the work pieces from one work support to the next.

21. An internal grinding machine comprising a bed, a plurality of spacedwork supports on the bed for peripheral engagement with work pieces, arotary drive wheel frictionally engaging the peripheries of the workpieces on the work supports for efiecting the rotation of said workpieces, a plurality of spaced grinding wheels carried by the bed, meansfor efiecting a radial feeding movement between the grinding wheels andthe work pieces and a subsequent retraction of the feeding movement,means to procure axial separation between the grinding wheels and thework pieces, and a work carrier for advancing the work pieces from onework support to the next while said grinding wheels are axiallywithdrawn from the work pieces, said carrier being actuated in timedrelation to the radial feeding means.

22. An internal grinding machine for grinding bores of hollowcylindrical workpieces, comprising a base, a plurality of work supportson the base for peripheral engagement with workpieces, a rotary drivewheel frictionally engaging the peripheries of the workpieces on theseveral supports for rotation thereof, means for holding the workpiecesagainst said work supports and drive wheel, and a grinding wheel foreach support carried by the base.

23. An internal grinding machine for grinding the bores of hollowcylindrical workpieces, comprising a base, a plurality of work supportson the base for peripheral engagement with workpieces, a rotary drivewheel frictionally engaging the peripheries of the workpieces for arotation thereof, and a grinding wheel for each work support carried bythe base and movable relative to said Work supports.

24. An internal grinding machine for grinding the bores of hollowcylindrical workpieces, comprising a base, a plurality of work supportson the base for peripheral engagement with workpieces, a rotary drivewheel frictionally engaging the peripheries of the workpiecesfor arotation thereof, a grinding wheel for each Work support carried by thebase and movable rela tive to said work supports for withdrawing thewheels from the bores of the workpieces, and

means for advancing the workpieces from one work support to the next.

25. An internal grinding machine comprising a base, a plurality ofcenterless work supporting structures on said base, each of saidstructures having a plurality of supporting members engageable with theperiphery of a workpiece, a grinding wheel for eachof said structurescarried by the base and movable relative to the structures, and acarrier for advancing workpieces from one supporting structure to thenext.

26. An internal grinding machine comprising a base, a plurality ofcenterless work supporting structures on said base, each of saidstructures having a plurality of supporting members engageable with theperiphery of a workpiece in said structure, one of said members beingcommon to all said structures, a grinding wheel for each of saidstructures carried by the base and movable relative to the structures,and a carrier for advancing workpieces from one supporting structure tothe next.

27. An internal grinding machine comprising a base, a rotary drive wheelon said base, a magazine, a plurality of work supports peripherallyspaced about the rotary drive wheel and defining spaced grindingstations, a grinding wheel for each grinding station, a work carrier foradvancing workpieces from one station to the next, and cooperating meanson the magazine and carrier for releasing workpieces from said magazine.

28. An internal grinding machine comprising a base, a rotary drive wheelon said base, a magazine, a plurality of work supports peripherallyspaced about the rotary drive wheel and defining spaced grindingstations, a grinding wheel for each grinding station, a work carrier foradvancing workpieces from one station to the next, cooperating means onthe magazine and carrier for releasing workpieces from said magazine,and means for intermittently actuating the carrier.

29. In a grinding machine, a base, a plurailty of centerlesswork-supporting structures on said base, each of said structurescomprising a plurality of supporting members engageable with theperiphery of a workpiece, a grinding wheel on said base for each of saidstructures, said wheels corresponding substantially in spacing to thespacing of the supporting structures, and a carrier for advancingworkpieces from one structure to the next.

30. In a grinding machine, a base, a plurality of centerlesswork-supporting structures on said base, each of said structurescomprising a pluraldefining spaced grinding stations, a plurality of 7sgrinding wheels corresponding in spacing substantially to the spacing ofthe work supports, a slide, and means for actuating said slide 'for arelative axial movement between the grinding wheels and workpieces onsaid work supports, and a second slide for procuring a transversemovement between said wheels and workpieces.

32. An internal grinding machine comprising a base, a plurality ofcenterless work-supporting structures on said base, each of saidsupporting structures comprising a plurality of work-supporting membersengageable with the periphery of a workpiece, one of said members beingpositively rotated for a rotation of the workpieces, a plurality ofspaced grinding wheels carried by the base, means for withdrawing saidgrinding wheels from operative relation to the workpieces in thework-supporting structures, and means for advancing the workpieces fromone supporting structure to the next while said grinding wheels are ininoperative position.

33. An internal grinding machine for grinding the bore of hollowcylindrical workpieces comprising a bed, a plurality of spaced worksupports on the bed for peripheral engagement with workpieces, a rotarydrive wheel frictionally engaging the peripheries of the workpieces foreifecting their rotation, a plurality of spaced grinding wheels carriedby the bed and movable relative to the workpieces, means for effecting aradial feeding movement between the grinding wheels and the workpiecesto reduce said workpieces.

34. An internal grinding machine comprising a base, a plurality ofcenterless work-supporting structures on said base, each of saidsupporting structures comprising a plurality of work-supporting membersengageable with the periphery of a work-piece, one of said members beingpositively rotated for-a rotation of the workpieces, a plurality ofspaced grinding wheels carried by the base, means for effecting a radialfeeding movement between the grinding wheels and the workpieces in thesupporting structures, means for withdrawing said grinding wheels fromoperative relation to the workpieces in the work-supporting structures,and means for advancing the workpieces from one supporting structure tothe next while said grinding wheels are in inoperative position.

35. In an internal grinding machine, a plurality of spaced grindingwheels, means for supporting and rotating an annular workpiece during agrinding operation on the bore thereof by each of said wheelssuccessively, said means including a regulating wheel and at least onework rest, said regulating wheel and work rest being engageable with theperiphery of the workpiece, means operative at the end of each grindingoperation for procuring a relative axial withdrawal movement between theoperative grinding wheel and the workpiece engaged thereby for removingthe wheel from the bore of the workpiece, and means for advancing saidworkpiece relative to said grinding wheels between successive grindingoperations and while the previously operative grinding wheel iswithdrawn from the bore of the workpiece, said advancing meanspositioning said workpiece in a position for engagement by thesucceeding grinding wheel.

36. In an internal grinding machine, a plurality of spaced grindingwheels, means for supporting and rotating an annular workpiece during agrinding operation on the bore thereof by each of said wheelssuccessively, said means including a regulating wheel and at least onework rest, said regulating wheel and work rest being engageable with theperiphery of the workpiece, means operative at the end of each grindingoperation for procuring a relative axial withdrawal movement between theoperative grinding wheel and the workpiece engaged thereby for removingthe wheel from the bore of the workpiece, and means for advancing saidworkpiece relative to said grinding wheels between successive grindingoperations and while the previously operative grinding wheel iswithdrawn from the bore of the work. piece, said advancing meanspositioning said workpiece in a position for engagement by thesucceeding grinding wheel, said advancing means also placing an ungroundworkpiece in position for engagement by the previously operativegrinding wheel during the successive grinding operation.

SOL EINSTEIN.

